Tone balance indicators



Jan. 21, 1964 R. A. MQ 3,118,422

TONE BALANCE INDICATORS Filed Dec. 18, 1961 2 Sheets-Sheet 1 INVENTOR. Richard E. m namara,

BY avfi 6 ATTORNEY Jan. 21, 1964 R. A. M NAMARA 3,118,422

TONE BALANCE INDICATORS Filed Dec. 18. 1961 2 Sheets-Sheet 2 Richard f2. m namara ATTORNEY United States Patent 3,118,422 TONE BALANCE INDICATORS Richard A. McNamara, Mount Prospect, IlL, assignor to Zenith Radio Corporation, Chicago, IlL, a corporation of Delaware Filed Dec. 18, 1961, Ser. No. 159,870 1 Claim. (Cl. 116124.4)

This invention is directed to a tone balance indicator and more specifically, to :an indicator for use with a sound reproducing system of the type having a plurality of adjustable control devices for varying respective performance characteristics of said system.

Tone balance indicators are commonly used with either FM radio or phonograph systems particularly those equipped for stereophonic sound reproduction. These indicators are associated with and indicate the adjustment of control devices which vary performance characteristics such as presence, treble and bass. All of these tone characteristics are inter-related from an audio standpoint and the adjustment of one may require adjustment of the other characteristics by the user in order to give a pleasing overall tone balance from this sound system.

In the past these tone balance indicators have utilized the adjustable knob of the control device itself as an indicator, have coupled the adjusting knob to independent indicators and scales, or have provided a single indicator acted upon by all of the tone control devices which purported to give a graphical characterization of the tone balance. All of the above devices have either confused the user of the sound reproducing system, given inadequate information, or have been expensive and complicated.

Accordingly, it is an object of this invention to provide an improved tone balance indicator.

It is a more specific object of this invention to provide a tone balance indicator which displays a correlated indication of a plurality of tone balance characteristics.

It is a further object of this invention to provide a tone balance indicator of simple and inexpensive construction.

It is yet another object of this invention to provide a tone balance indicator which conveys tone balance information in a manner that the ordinary user of the device may adequately comprehend the information displayed.

In accordance with the invention, a tone balance indicator or the like is provided for use in conjunction with a sound reproducing system of the type having a plurality of adjustable control devices for varying respective performance characteristics of the system, the indicator comprising a display panel having a plurality of sectors each provided with calibrating indicia representative of various adjustments of a corresponding one of the control devices. A light source is provided and in addition, means including a plurality of independently movable light-channeling devices, one for each of the control devices, direct light spots from the light source to the respective sectors of the display panel in registration with the calibrating indicia. Means are coupled to the control devices and are responsive to their adjustment for moving the light channeling devices to vary the positions of the light spots within their respective sectors in accordance with respective variations in the adjustments of the control devices.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claim. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:

FIGURE 1 is a front plan view of a panel of an audio amplifier and radio tuner on which is mounted a tone balance indicator embodying the invention;

3,118,422 Patented Jan. 21, 1964 FIGURE 2 is an enlarged front plan view of a portion of the panel of FIGURE 1 partially cut-away to reveal the operating mechanism; and

FIGURE 3 is a sectional view taken along line 33 of FIGURE 2.

Referring now particularly to FIGURE 1 of the drawings, the reference character 10 designates a control panel which is placed in front of the tuner and amplifier of an AM-FM radio. Panel 10 is provided with a treble control knob 11, :a presence control knob '12 and a bass control knob 13 which are arranged to permit adjustment of respective control devices in the audio amplifier in conventional fashion. Since the audio amplifier per se forms no part of this invention, its details are not disclosed. The panel is mounted on a frame to be described later along with a light-transmissive circular display panel 15 which is mounted in a circular frame =14 and has three sectors 11a, 12a and 13a which are provided with calibrating indicia representative of various adjustments of the correspondingly numbered control knobs 11, 12 and 13.

The remainder of panel 10 contains AM and FM radio dial scales l6 and 17 along with an indicator 18. Both the scales 16 and I7 and display panel 15 are protected by a rectangulm glass plate 2% which is mounted in panel 19. The panel also has mounted on it five additional knobs on the lower portion of the panel which control various operating characteristics such as tuning, on-off, etc.

Referring now to FIGURE 3 a sectional view of panel 10 is shown with glass plate 20 covering display panel 15. A frame 21 retains panel 19 by means of fasteners 22 of which only one is shown in FIGURE 3 and also retains circular display panel frame '14.

Three independently movable light-channeling devices 11b, 12b and 13.), two of which are shown in FIGURE 3, are associated with the correspondingly numbered control knobs. The light-channeling devices are more commonly referred to as light pipes and are rod-like elements which conduct light internally without substantial diffusion. They may be formed of a transparent plastic suitable for this purpose, as for example a plastic composition such as methyl methacrylate known commercially as Lucite. Rods 11b, 12b and 13b are journalled in bearings 11c, 12c and 130 respectively which are mounted on a sub-frame 21:: which in turn is mounted on frame 21 by fasteners 24. In line with the rotational axis of each light-pipe is a light bulb one of which is shown in FIG- URE 3 and designated 12:1. The light source comprises three such bulbs mounted on sub-frame Zlla, each bulb being closely juxtaposed with an end termination of one of the light-pipes, as illustrated for the bulb 12d and lightpipe in FIGURE 3. Each light-pipe has a second end termination '11), 12 and 13 which is offset from its axis of rotation and is in close proximity to display panel 15. Light from bulbs 12d, etc. is directed to these second end terminations to form light spots which register with the calibrating indicia of sectors 11a, 12a and 13a of display panel 15. With rotation of controls 11, 12 and 13, the light spots move along arcuate paths between plus and minus limits of each sector, as shown in FIGURE 2 by the dashed arrows in sectors 11a and 13a.

Control knobs 11, 12 and 13 are coupled to control devices such as 22, only one of which is shown in FIG- URE 3, by control shafts such as 23. The control device may be a rheostat or potentiometer which is electrically connected in the audio amplifier circuit in conventional fashion.

Control shaft 23 is coupled to light-pipe 12b by a fleX- ible drive pulley 25 such as those employed in conventional tuning indicators of AM and FM radios. Drive pulley 25 constitutes means. coupled to control device 22 and responsive to adjustment thereof for moving lightchanneling device 12b to vary the position of the light spot produced thereby Within the associated sector 211 of the display panel 15 in accordance with the variation in adjustment of knob 12.

Operation When the user wishes to adjust the tone balance of his receiver, he rotates one or all of knobs 11, 12 and 13. Rotation of the knob operates the control device which adjusts the tone balance characteristic and also rotates the light spot indicator on display panel 15. As a specific example, suppose the user wishes to reduce the amount of bass response of his receiver. He adjusts knob 13 rotating the knob in a counterclockwise direction to move the light spot on end termination 13 in sector 13a in a counterclockwise direction toward the minus sign indication on the sector. If an increase of bass response is desired, the light spot should be moved toward the plus sign. Treble response and presence may be adjusted similarly.

As shown in FIGURE 1 the light spots and their corresponding indicia sectors are all located on circular display panel 15 thus providing the user of the tone balance indicator a correlated indication of all of the tone balance characteristics. Furthermore, the tone balance characteristics are displayed in a manner which permits the ordinary user of the receiver to quickly comprehend the information displayed. Lastly, the tone balance indicator is of simple and inexpensive construction.

While a particular embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and, therefore, the aim in the appended claim is to cover all such changes and modifications as fall Within the true spirit and scope of the invention. 1

I claim:

A tone balance indicator or the like for use in conjunction with a sound reproducing system of the type having a plurality of adjustable control devices for varying respective performance characteristics of said system, said indicator comprising: a light transmissive circular display panel having a plurality of sectors each provided with radial lines serving as calibrating indicia representative of various adjustments of a corresponding one of said control devices; a frame for retaining said display panel; a light source including at least one lamp fixed to said frame; a plurality of independently movable light-piping devices, one for each of said control devices, each of said light-piping devices comprising a rod of light conducting material having a diameter small with respect to its length and having one end journalled in said frame juxtaposed With respect to said light source and the other end disposed for movement in a plane in close proximity and parallel to said display panel for directing light from said source to an assigned one of said sectors of said display panel; a first plurality of pulley means each mounted for rotation with one of said light piping devices; a second plurality of pulley means each mechanically associated with one of said control devices; and a plurality of flexible belts linking said first and second pulley means for coupling said control devices to said light-piping devices and responsive to the adjustment of said control devices, respectively, for rotating said light-piping devices in accordance with respective variations in the adjustments of said control devices.

References Cited in the file of this patent UNITED STATES PATENTS 2,035,998 ,Thompson Mar. 31, 1936 2,671,284 Hyland Feb. 16, 1937 2,106,152 Mattes Jan. 18, 1938 2,333,492 Ridge Nov. 2, 1943 2,392,581 De Juhasz Jan. 8, 1946 2,672,116 G-underson Mar. 16, 1954 2,756,714 Nolte July 31, 1956 

